1. Field of the Invention
The present invention relates to a headrest for motor vehicle and more particularly, to a headrest mounting structure, which is adjustable to fit the pitch between the two headrest mounting holes of any of a variety of vehicle seats.
2. Description of the Related Art
Following the prosperity of the society, people do care about the outer appearance design as well as the comfortable status of the internal upholstery when buying a car. Nowadays, a car is not simply a transportable vehicle. A modern car may be equipped with stereo system, hand-free handset, VCD player, multimedia system, etc. In order to fully utilize the limited internal space of a car, the headrest of the driver' seat or front seat may be used to support a LCD monitor. However, an old model car does not provide a LCD monitor. When wishing to install a LCD monitor in a seat in an old model car, the headrest of the seat must be taken away so that a new headrest that is equipped with a LCD monitor can be used as a substitute. However, different vehicle seats may use different sizes of headrests. In order to fit different vehicle seats, suppliers and distributors must provide different sizes of headrests for selection. Preparing different sizes of headrests is a big burden to inventory control.
FIG. 4 shows a headrest B installed in a vehicle seat A according to the prior art. According to this design, the headrest B comprises a support frame C1 fixedly mounted inside the headrest B, and two mounting rods C2 downwardly extending from the support frame C1 and arranged in parallel for inserting into a respective headrest mounting hole A1 at the top side of the vehicle seat A. According to this design, the mounting rods C2 are not detachable. Because the mounting rods C2 protrude over the bottom side of the headrest B at a distance, the headrest B occupies much storage space. During delivery, the headrest B requires much packing material. Further, because the pitch between the two mounting rods C2 is not adjustable, this design of headrest B fits only one particular model of vehicle seat A.
In order to eliminate the drawbacks of the aforesaid headrest design, an adjustable headrest that fits different vehicle seats is disclosed. According to this design, as shown in FIG. 5, the headrest B comprises a base frame D, a clamping plate D1 provided at the front side of the base frame D, a locating bar D2 horizontally set between the base frame D and the clamping plate D1, two mounting blocks D3 slidably mounted on the locating bar D2, two tightening up screws D31 respectively fastened to the mounting blocks D3 to lock the mounting blocks D3 to the locating bar D2 at the desired location, and two stems D4 respectively fastened to the mounting blocks D3 through a respective screw joint for fastening the headrest B to a vehicle seat. This design of headrest B is adjustable to fit vehicle seats. However, when adjusting the pitch between the two stems D4 (the mounting blocks D3), the user must detach the parts of the headrest B (because the adjusting structure is kept inside the headrest B). This adjustment procedure is complicated. When detaching the parts of the headrest B, the leather covering or stuffing sponge may be damaged accidentally. Further, the tightening up screws D31 may be loosened upon vibration of the car. When the tightening up screws D31 are loosened, the headrest B may vibrate or displace, and the user must open the headrest B and fasten tight the tightening up screws D31 again.
FIGS. 6 and 7 show still another structure of the headrest mounting structure according to the prior art. According to this design, the headrest B comprises a base frame E mounted inside the headrest B, the base frame E having an upwardly extending support frame E1, a chamber E2 and bottom through holes E21 in communication with the chamber E2, an axle F mounted in the chamber E2 of the base frame E and having a screw hole F1 in each end, two support rods G respectively inserted through the bottom through holes E21 of the base frame E, the support rods G each having an angled screw tip G1 respectively threaded into the screw holes F1 at the ends of the axle F, and a U-shaped locating plate H fastened to the axle F and the base frame E to secure the axle F to the base frame E firmly in position. Because the support rods G are respectively fastened to the axle F through a respective screw joint, the support rods G can be adjusted relative to the axle F to further adjust the pitch between the support rods G. When assembled, the support rods G are fastened to respective headrest mounting holes A1 of the vehicle seat A. This design of headrest is functional; however it needs to open the headrest B when wishing to adjust the pitch between the support rods G. Further, because the support rods G are respectively fastened to the axle F through a respective screw joint, the user can only adjust the pitch between the support rods G within a short distance.
Further, the complicated procedure of adjusting the pitch between the support rods G of the headrest B shown in FIGS. 6 and 7 or the pitch between the two the two stems D4 (the mounting blocks D3) of the headrest B shown in FIG. 5 can only be done by a skilled professional person. The car owner shall have to pay an extra installation fee to the supplier.